Equipping a book of law allows the player to preach and perform ceremonies, such as blessing, last rites, and wedding rites, by operating it (none of which have any effect on the game itself, and are simply recited lines of text), costing 25% of the player's special attack energy.

Lost books of law can be reclaimed by speaking to Jossik, complete with all pages that have been added, for no cost. Alternatively, for those who do not wish to travel to the lighthouse, Perdu will return them to players for 12,000 coins.

The completed book has the fourth highest ranged bonus of all off-hand items, following just behind the odium ward.